A high-strength wear-resistant slide rail prefabricated part, its preparation method and application

Abstract

The present invention relates to the technical field of green special refractory ceramics, and specifically relates to a high-strength wear-resistant slide rail prefabricated part, a preparation method thereof and an application. The slide rail prefabricated part comprises the following raw material components in percentage by weight: 39.5-90% of mullite particles, 3.3-10% of alumina powder, 2.4-10% of calcium aluminate cement, 2.4-10% of silica fume, 0-30% of alumina hollow spheres, 0.1-0.5% of water reducing agent; the mullite is composed of the following particle size gradations: 10-30% of 5-8 mm; 10-40% of 3-5 mm; 10-30% of 1-3 mm; 0-70% of 0-1 mm; the alumina powder is composed of calcined alumina powder with a particle size d 50 of 4-6 µm, activated alumina powder with a particle size d 50 of 1-2 µm and trehalose composite α-alumina powder with a particle size d 50 of 8-10 µm mixed together. The slide rail prefabricated part has excellent high-temperature strength, corrosion resistance and thermal shock resistance, and significantly improves the service life of the slide rail.

Description

Technical Field

[0001] The present invention relates to the technical field of green special refractory ceramics, and more specifically, it relates to a high-strength wear-resistant slide rail prefabricated part, its preparation method and application. Background Art

[0002] Industrial heating is an important part of the manufacturing industry. Industrial furnaces are important equipment for industrial heating and develop synchronously with the development of the industry. There are many types of industrial furnace equipment, which are large in quantity and wide in scope, covering all walks of life and having a wide impact. Among them, forging heating furnaces are one of the important equipment in the metal processing industry, mainly used for heating metal materials. During the forging process, the temperature in the furnace is about 800°C - 1250°C, the heating rate reaches 100°C / min, and the furnace temperature fluctuates greatly. As the load-bearing and guiding part, the slide rail of the heating furnace undertakes the sliding function of the steel billet under high-temperature environment.

[0003] The slide rail bricks of heating furnaces are usually made of refractory bricks, refractory castables or other high-temperature refractory materials, which have good anti-wear, high-temperature resistance and chemical erosion resistance, and can be used as sliding supports and heat insulation layers to be better applied in heating equipment (such as industrial furnaces and furnace chambers). However, the slide rail prefabricated parts used in many current heating furnaces still face multiple technical problems, such as: poor high-temperature resistance: most of the existing slide rail materials use conventional alloy steels or carbon steels, and these materials are prone to deformation, oxidation and wear under long-term high temperature, resulting in the failure of the slide rail and increasing the maintenance cost; short replacement cycle: traditional slide rails often need to be replaced frequently due to friction and high-temperature damage during use, affecting production efficiency; insufficient surface wear resistance: the surface of the slide rail is in direct contact with metal workpieces, and is extremely prone to wear and corrosion. Summary of the Invention

[0004] In order to solve at least one of the above technical problems, the present invention provides a high-strength wear-resistant slide rail prefabricated part, its preparation method and application. By selecting reasonable raw materials of the castable and the content of each component, the slide rail prefabricated part has excellent high-temperature strength, corrosion resistance and thermal shock resistance, significantly improving the service life of the slide rail.

[0005] In the first aspect, the present invention provides a high-strength wear-resistant slide rail prefabricated part, which comprises the following raw material components by weight percentage: mullite particles 39.5 - 90%, alumina powder 3.3 - 10%, calcium aluminate cement 2.4 - 10%, silica fume 2.4 - 10%, alumina hollow spheres 0 - 30%, water reducer 0.1 - 0.5%;

[0006] The mullite is composed of the following particle size distribution, and the particle size and the weight percentage of each particle size in the mullite are: 5 - 8mm 10 - 30%; 3 - 5mm 10 - 40%; 1 - 3mm 10 - 30%; 0 - 1mm 0 - 70%;

[0007] The alumina powder is composed of calcined alumina powder with a particle size d 50 of 4 - 6 µm, activated alumina powder with a particle size d 50 of 1 - 2 µm, and trehalose composite α-alumina powder with a particle size d 50 of 8 - 10 µm, which are mixed together.

[0008] The slide rail prefabricated part of the present invention selects mullite as the main aggregate, which has a relatively high melting point (about 1850 °C) and load softening temperature, excellent oxidation resistance, acid and alkali corrosion resistance, and high-temperature creep resistance. It has a small deformation under load and a low thermal expansion coefficient (5.3x10 -6 K), thereby enabling the slide rail prefabricated part to have excellent thermal shock resistance.

[0009] Among them, in the present invention, mullite adopts four particle size ranges each accounting for a certain proportion to achieve multi-level particle size mutual filling (large particles form the skeleton, and small particles fill the gaps). Specifically, large particles (5 - 8 mm) form a crack deflection structure to slow down the crack propagation rate, and then medium particles (1 - 5 mm) improve the fracture toughness through the interface locking effect; finally, fine particles (0 - 1 mm) fill the pores to limit the stress concentration under thermal shock, effectively reducing the sintering shrinkage rate of the product.

[0010] On the basis of the above multi-level particle size mullite, the present invention also adds a set amount of alumina powder, calcium aluminate cement, silica fume, alumina hollow spheres, and water reducing agent. Among them, the alumina powder can fill the pores between mullite particles and form a high-purity alumina crystal phase, improving the refractoriness (>1700 °C) and slag erosion resistance; calcium aluminate cement is used as a binder, which can hydrate to form a hydrated calcium aluminate binding phase at room temperature to provide initial strength, and generate a calcium aluminate ceramic phase after high-temperature dehydration, avoiding excessive shrinkage and cracking; silica fume is nano-scale SiO2; on the one hand, it can cooperate with Al2O3 to fill the micropores between mullite particles, and on the other hand, it can react with Al2O3 at high temperature to generate mullite, further improving the densification and hot strength of the slide rail prefabricated part; the alumina hollow spheres can reduce the thermal conductivity (can be <1.0 W / m·K) and reduce the density (can be <1.5 g / cm³) through spherical pores; finally, with a set amount of water reducing agent, the particles are dispersed by electrostatic repulsion, reducing the water-binder ratio (improving the workability), and at the same time reducing the drying shrinkage and cracking.

[0011] In addition, the present invention further limits the composition of the alumina powder. This is because calcined alumina has high stability and is suitable for high-temperature environments; activated alumina has a large surface area and better reaction activity; while trehalose composite α-alumina introduces the organic component trehalose, which can affect the sintering behavior and material properties to a certain extent. In addition, since particle size differences can affect the packing density and particle arrangement during sintering, the present invention also controls the particle size of the alumina powder in a gradient manner. Among them, 8-10 µm trehalose composite α-alumina with a large particle size serves as the main framework, 4-6 µm calcined alumina serves as the relay support, and finally 1-2 µm activated alumina fills the gaps, thereby significantly increasing the density of the slide rail preform.

[0012] Thus, the slide rail preform obtained by the present invention has excellent high-temperature strength, corrosion resistance, and thermal shock resistance, and can significantly improve the service life of the slide rail.

[0013] Preferably, the weight ratio of the calcined alumina powder, activated alumina powder, and trehalose composite α-alumina powder is 1-6:3-9:85-96.

[0014] Adopting the above technical solution, the alumina powder of the present invention is mainly composed of trehalose composite α-alumina powder. This is because when preparing the slide rail preform, water is usually added and mixed with the components. At this time, the trehalose in the trehalose composite α-alumina powder dissolves in water, which can improve the fluidity of each component and make the slide rail preform easier to form; in the forming stage of the slide rail preform, the dissolved trehalose can further fill the gaps between the ceramic particles and crystallize, thereby enhancing the bonding force between the particles and effectively increasing the strength and stability of the slide rail preform; in the sintering stage of the slide rail preform, trehalose dehydrates and carbonizes at high temperature, and then transforms into amorphous carbon with a graphene-like structure, effectively improving the toughness and wear resistance of the slide rail preform; in addition, the generated carbon will also react with alumina in the components at high temperature to form aluminum carbide and react with silicon dioxide to form silicon carbide, and these reactions will further enhance the mechanical properties and thermal stability of the ceramic. Therefore, throughout the process, the role of trehalose is not only as a plasticizer and binder, but also transforms into a functional carbon material during subsequent high-temperature treatment, which not only changes the microstructure of the slide rail preform, but also endows the slide rail preform with more excellent high-temperature resistance and thermal shock resistance.

[0015] In addition, compared with the method of adding trehalose alone, the present invention can obtain a slide rail preform with more excellent thermal shock resistance in a composite state; this may be because through the composite process, trehalose coats the surface of α-aluminum oxide particles in a molecular layer, avoiding excessive local concentration caused by agglomeration during direct addition, thereby improving the uniformity and performance of the material; secondly, during high-temperature treatment, trehalose will decompose or volatilize during sintering. Pre-combining trehalose with α-aluminum oxide can better form an interface bond to form a uniform porous structure; furthermore, the initial temperature of thermal decomposition of trehalose after compounding is increased from 160 °C to 300 °C, avoiding premature decomposition during the mixing or drying stage and causing process out of control.

[0016] Preferably, the preparation method of the trehalose composite α-aluminum oxide powder comprises the following steps:

[0017] Mix the α-aluminum oxide powder with the trehalose solution to make a slurry, inject the slurry into a mold for vibration degassing, place it in an environment with a humidity of 80-100% and a temperature of 30-40 °C for curing for 24-48 h, and after demolding, place it at 100-150 °C for low-temperature pre-sintering, and grind it after removing moisture to obtain.

[0018] The present invention adopts the method of vibration degassing + mold forming, which helps the slurry to be more dense. Combined with high-humidity curing (80-100% RH), the hydrogen bond network of trehalose mediated by water molecules penetrates the pores on the surface of α-aluminum oxide to form a chemical adsorption layer, which can effectively reduce the problem of easy shedding of physical adhesion caused by mechanical mixing; on this basis, the present invention further limits the pre-sintering temperature to 100-150, which is lower than the decomposition threshold of trehalose (160 °C), so that its carbon precursor function can be retained. Compared with the traditional high-temperature sintering (>500 °C) process, it can reduce the pollution of the alumina lattice by the cracking products; the above steps are independently controllable and the steps are simple and convenient, suitable for large-scale production.

[0019] Preferably, the weight ratio of the α-aluminum oxide powder to trehalose is 3:1.

[0020] Adopting the above technical solution, when the proportion of trehalose is 25% (3:1), it can not only form an effective coating layer to enhance the interfacial bonding force, but also avoid excessive introduction leading to too high porosity after high-temperature carbonization, and can also ensure that the trehalose solution fully wets the surface of the α-aluminum oxide powder to prevent local agglomeration; in addition, when the content of trehalose ≤ 25%, the pollution of its thermal decomposition residue to the α-aluminum oxide lattice is controllable (residual carbon content < 1.5%), and thus the process stability in the pre-sintering stage (100-150 °C) can be ensured.

[0021] Preferably, the alumina content in the aluminate cement is 65-70%, and the calcium oxide content is 29-33%.

[0022] Adopting the above technical solution, a high alumina content (65 - 70%) can endow aluminate cement with excellent refractory properties (refractoriness can reach above 1600 °C), enabling it to maintain structural stability at high temperatures, not being easily softened or melted. Additionally, it can have strong resistance to the erosion of chemical media such as sulfates and weak acids, thereby further improving the erosion resistance and high-temperature strength of the slide rail precast. Moreover, with the combination of the above-mentioned specific alumina powder in the present invention, it can improve the late shrinkage or micro-expansion of aluminate cement caused by a high calcium content (29 - 33% CaO), thereby effectively reducing the risk of cracking in a dry environment.

[0023] Preferably, the purity of the alumina hollow spheres ≥ 99%, the particle size is 0.2 - 0.5 mm, and its bulk density is 0.8 - 0.9 g / cm 3 。

[0024] Adopting the above technical solution, the alumina hollow spheres have low impurity content, relatively concentrated particle size dimensions, good fluidity, which is convenient for filling molds or preparing uniform composites; its hollow structure has low thermal conductivity, can reduce the solid-phase heat transfer path, relieve thermal stress, reduce the risk of cracking under high-temperature sudden changes, and can also reduce the overall weight of the material to a certain extent.

[0025] Preferably, the water reducing agent is at least one of sodium tripolyphosphate, sodium hexametaphosphate, and boric acid.

[0026] Adopting the above technical solution, both sodium tripolyphosphate and sodium hexametaphosphate are condensed phosphates, which can disperse cement particles through the adsorption-desorption mechanism. The weak acidity of boric acid can adjust the pH value of the slurry (pH 7.5 - 8.5), relieve the excessive delay of cement setting in the alkaline environment of phosphates. Thus, an appropriate water reducing agent can be selected according to the requirements of different alkaline water systems.

[0027] In a second aspect, the present invention provides a method for preparing the above high-strength wear-resistant slide rail precast, comprising the following steps:

[0028] Take a set amount of raw material components, add water accounting for 4.5 - 5.5% of the total weight of the raw material components and mix, vibrate and mold after stirring, cure for 20 - 30 h under the conditions of a temperature of 20 - 50 °C and a relative humidity of 80 - 100%, after demolding, heat up to 110 - 115 °C at a rate of 10 - 20 °C / h and keep warm for 24 - 48 h, then heat up to 350 °C at a rate of 15 - 30 °C / h, keep warm for 24 - 48 h, and finally heat up to 600 °C at a rate of 15 - 20 °C / h, keep warm for 16 - 32 h to obtain the high-strength wear-resistant slide rail precast.

[0029] With the above technical solutions, when the water content of the present invention is controlled at 4.5 - 5.5%, it can ensure fluidity while avoiding the loose structure caused by excessive moisture. Controlling the temperature and humidity curing (20 - 50°C, 80 - 100% RH) may promote the hydration reaction of the material, form a dense network structure, and thus enhance the strength. In addition, the coordinated control of temperature and humidity can accelerate the early strength development and inhibit the microcracks caused by too high temperature; the segmented heating heat treatment, in which the initial heat preservation at 110 - 115°C (24 - 48 h) first removes the free water and residual stress, the medium-temperature heat preservation at 350°C (24 - 48 h) can promote the mineral phase transformation, and the high-temperature heat preservation at 600°C (16 - 32 h) can strengthen the grain boundary bonding. On this basis, the segmented rate control is carried out to avoid the microstructural phase change stress caused by temperature mutation, and thus contribute to reducing the internal stress and optimizing the grain structure.

[0030] In the third aspect, the present invention provides an application of the above high-strength wear-resistant slide rail prefabricated part in the slide rail of a forging heating furnace.

[0031] In summary, the present invention has the following beneficial effects:

[0032] 1. The present invention uses mullite (low expansion coefficient) with a specific particle size, alumina powder, and alumina hollow spheres (stress buffering) to synergistically reduce the risk of thermal stress cracking and improve the thermal shock resistance of the slide rail prefabricated part; and then uses calcium aluminate cement and silica fume to react at high temperature to form a continuous ceramic network. The obtained slide rail prefabricated part has excellent high-temperature strength, corrosion resistance, and thermal shock resistance, and can significantly improve the service life of the slide rail.

[0033] 2. The alumina powder of the present invention uses large-particle-size 8 - 10 µm trehalose composite α-alumina as the main framework, 4 - 6 µm calcined alumina as the relay support, and finally 1 - 2 µm activated alumina fills the gaps, thereby endowing the slide rail prefabricated part with more excellent high-temperature resistance, toughness, and wear resistance;

[0034] 3. When preparing the slide rail prefabricated part, the present invention uses high-humidity curing and the coordinated control of temperature and humidity to optimize the hydration structure of the material, and then uses stepped heating and segmented rate control to reduce internal defects and avoid the microstructural phase change stress caused by temperature mutation, thereby ensuring the excellent high-temperature strength, corrosion resistance, and thermal shock resistance of the slide rail prefabricated part. Specific Embodiments

[0035] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0036] The raw materials of the present invention are all derived from conventional commercially available products. It should be specially noted that:

[0037] Among the alumina powders, the calcined alumina is a commercially available product with a particle size d 50 of 4 - 6 μm and a purity ≥ 98.5%; the activated alumina is a commercially available product with a particle size d 50 of 1 - 2 μm, a purity ≥ 92%, and a specific surface area ≥ 500 m² / g; the α-alumina powder is a commercially available product with a particle size d 50 of 3 - 5 μm, a purity ≥ 95%, and a specific surface area of 3 - 5 m 2 / g; the trehalose is an analytical standard product with HPLC ≥ 98%.

[0038] In addition, the aluminate cement preferably used in the present invention has an alumina content of 65 - 70% and a calcium oxide content of 29 - 33%; the alumina hollow spheres preferably have a purity ≥ 99%, a particle size of 0.2 - 0.5 mm, and a bulk density of 0.8 - 0.9 g / cm 3 ; the water reducing agent is preferably at least one of sodium tripolyphosphate, sodium hexametaphosphate, and boric acid.

[0039] Preparation examples of trehalose composite α-alumina powder

[0040] Preparation example 1

[0041] Mix the α-alumina powder with the trehalose solution to make a slurry. The weight ratio of the α-alumina powder to the trehalose is 3:1, and the solid content of the slurry is controlled to be 20%; inject the slurry into a mold, vibrate to exhaust air, place it in an environment with a humidity of 90% and a temperature of 35°C for 36 h of curing, demold and then place it at 120°C for low-temperature pre-sintering, and grind it to a particle size d 50 of 8 - 10 μm to obtain the composite alumina powder 1.

[0042] Preparation example 2

[0043] Mix the α-alumina powder with the trehalose solution to make a slurry. The weight ratio of the α-alumina powder to the trehalose is 3:1, and the solid content of the slurry is controlled to be 20%; inject the slurry into a mold, vibrate to exhaust air, place it in an environment with a humidity of 80% and a temperature of 30°C for 48 h of curing, demold and then place it at 100°C for low-temperature pre-sintering, and grind it to a particle size d 50 of 8 - 10 μm to obtain the composite alumina powder 2.

[0044] Preparation example 3

[0045] Mix α-aluminum oxide powder with trehalose solution to make a slurry. The weight ratio of α-aluminum oxide powder to trehalose is 3:1, and control the solid content of the slurry to be 20%. Inject the slurry into a mold, vibrate to exhaust air, and cure it in an environment with a humidity of 100% and a temperature of 40 °C for 24 h. After demolding, place it at 150 °C for low-temperature pre-sintering, remove the moisture, and grind it to a particle size d 50 of 8 - 10 μm to obtain composite alumina powder 3.

[0046] Preparation Example 4

[0047] Mix α-aluminum oxide powder with trehalose solution to make a slurry. The weight ratio of α-aluminum oxide powder to trehalose is 3:1, and control the solid content of the slurry to be 20%. Inject the slurry into a mold, vibrate to exhaust air, and cure it in an environment with a humidity of 65% and a temperature of 35 °C for 36 h. After demolding, place it at 120 °C for low-temperature pre-sintering, remove the moisture, and grind it to a particle size d 50 of 8 - 10 μm to obtain composite alumina powder 4.

[0048] Preparation Example 5

[0049] Mix α-aluminum oxide powder with trehalose solution to make a slurry. The weight ratio of α-aluminum oxide powder to trehalose is 3:1, and control the solid content of the slurry to be 20%. Inject the slurry into a mold, vibrate to exhaust air, and cure it in an environment with a humidity of 90% and a temperature of 35 °C for 36 h. After demolding, place it at 180 °C for pre-sintering, remove the moisture, and grind it to a particle size d 50 of 8 - 10 μm to obtain composite alumina powder 5.

[0050] Preparation Example 6

[0051] Mix α-aluminum oxide powder with trehalose solution to make a slurry. The weight ratio of α-aluminum oxide powder to trehalose is 2:1, and control the solid content of the slurry to be 20%. Inject the slurry into a mold, vibrate to exhaust air, and cure it in an environment with a humidity of 90% and a temperature of 35 °C for 36 h. After demolding, place it at 120 °C for low-temperature pre-sintering, remove the moisture, and grind it to a particle size d 50 of 8 - 10 μm to obtain composite alumina powder 6.

[0052] Preparation Example 7

[0053] Mix α-aluminum oxide powder with trehalose solution to make a slurry. The weight ratio of α-aluminum oxide powder to trehalose is 4:1, and control the solid content of the slurry to be 20%. Inject the slurry into a mold, vibrate to exhaust air, and cure it in an environment with a humidity of 90% and a temperature of 35 °C for 36 h. After demolding, place it at 120 °C for low-temperature pre-sintering, remove the moisture, and grind it to a particle size d 50 of 8 - 10 μm to obtain composite alumina powder 7.

[0054] The present invention will be further described in detail below in conjunction with examples and comparative examples. Example Example 1

[0055] The preparation method of the high-strength wear-resistant slide rail prefabricated part of this example includes the following steps:

[0056] Accurately weigh 800 g of mullite particles, 50 g of alumina powder, 30 g of calcium aluminate cement, 30 g of silica fume, 87 g of alumina hollow spheres, and 3 g of water reducing agent for standby;

[0057] Among them, the mullite is composed of the following particle size distribution, and the particle size and weight percentage of each particle size in the mullite are: 5-8 mm 20%, 3-5 mm 35%, 1-3 mm 25%, 0-1 mm 20%; the alumina powder has a particle size d 50 of 4-6 µm calcined alumina powder, a particle size d 50 of 1-2 µm activated alumina powder, and a particle size d 50 of 8-10 µm trehalose composite α-alumina powder (composite alumina powder 1) are mixed in a weight ratio of 4:6:90; the aluminate cement is CA-70, in which the alumina content is 68% and the calcium oxide content is 30%; the purity of the alumina hollow spheres ≥99%, the particle size is 0.2-0.5 mm, and its bulk density is 0.85 g / cm 3 ; the water reducing agent is sodium tripolyphosphate.

[0058] Add 5.0% of water based on the total weight of the raw material components to the above raw materials, mix, stir, vibrate and form, cure for 25 h under the conditions of a temperature of 40 °C and a relative humidity of 90%, after demolding, heat up to 110 °C at a rate of 15 °C / h and keep warm for 36 h, then heat up to 350 °C at a rate of 25 °C / h, keep warm for 36 h, and finally heat up to 600 °C at a rate of 18 °C / h, keep warm for 24 h to obtain the above slide rail prefabricated part.

[0059] Examples 2-5

[0060] Based on the method of Example 1, Examples 2-5 adjust the dosage of the raw material components. For details, see Table 1 below.

[0061] Table 1 Raw material component table of Examples 1-5 (unit: g)

[0062] Example 1 Example 2 Example 3 Example 4 Example 5 Mullite particles 800 395 640 800 900 Aluminum oxide powder 50 100 40 50 33 Calcium aluminate cement 30 100 24 50 33 Silica fume 30 100 24 50 33 Aluminum oxide hollow spheres 87 300 269 47 0 Water reducing agent 3 5 3 3 1

[0063] Examples 6-8

[0064] Examples 6 - 8 Based on the method of Example 1, the particle size distribution of mullite was adjusted. Among them, in Example 6, mullite was composed of the following particle size distribution, and the particle size of each particle size range and its weight percentage in mullite were: 5 - 8 mm 10%, 3 - 5 mm 10%, 1 - 3 mm 10%, 0 - 1 mm 70%; in Example 7, mullite was composed of the following particle size distribution, and the particle size of each particle size range and its weight percentage in mullite were: 5 - 8 mm 30%, 3 - 5 mm 40%, 1 - 3 mm 30%, 0 - 1 mm 0%; in Example 8, mullite was composed of the following particle size distribution, and the particle size of each particle size range and its weight percentage in mullite were: 5 - 8 mm 25%, 3 - 5 mm 25%, 1 - 3 mm 25%, 0 - 1 mm 25%.

[0065] Examples 9 - 11

[0066] Examples 9 - 11 Based on the method of Example 1, the composition of alumina powder was adjusted.

[0067] Among them, the alumina powder in Example 9 was mixed by calcined alumina powder, activated alumina powder and trehalose composite α - alumina powder (composite alumina powder 1) in a weight ratio of 1:3:96; the alumina powder in Example 10 was mixed by calcined alumina powder, activated alumina powder and trehalose composite α - alumina powder (composite alumina powder 1) in a weight ratio of 6:9:85; the alumina powder in Example 11 was mixed by calcined alumina powder, activated alumina powder and trehalose composite α - alumina powder (composite alumina powder 1) in a weight ratio of 1:1:1.

[0068] Examples 12 - 17

[0069] Examples 12 - 17 Based on the method of Example 1, the trehalose composite α - alumina powder (composite alumina powder 1) in the alumina powder was replaced. Among them, composite alumina powder 2 was used in Example 12, composite alumina powder 3 was used in Example 13, composite alumina powder 4 was used in Example 14, composite alumina powder 5 was used in Example 15, composite alumina powder 6 was used in Example 16, and composite alumina powder 7 was used in Example 17.

[0070] Examples 18 - 19

[0071] Examples 18 - 19 Based on the method of Example 1, the aluminate cement was replaced. Among them, CA - 50 was specifically used as the aluminate cement in Example 18, with an alumina content of 55% and a calcium oxide content of 38%; CA - 80 was specifically used as the aluminate cement in Example 19, with an alumina content of 75% and a calcium oxide content of 13%. Example 20

[0072] Example 20 On the basis of the method of Example 1, the alumina hollow spheres were replaced. Specifically, those with a purity of ≥99%, a particle size of 1.0 - 1.5 mm, and a bulk density of 0.80 g / cm 3 .

[0073] Examples 21 - 23

[0074] Examples 21 - 23 On the basis of the method of Example 1, the parameters of the preparation method of the high-strength wear-resistant slide rail prefabricated parts were adjusted.

[0075] Among them, the adjustment in Example 21 was as follows:

[0076] Add 4.5% of water by weight of the total raw material components to the raw materials, mix them, vibrate and mold them after stirring, cure them for 30 h under the conditions of a temperature of 20°C and a relative humidity of 100%, heat them to 115°C at a rate of 10°C / h and keep them warm for 24 h after demolding, then heat them to 350°C at a rate of 15°C / h, keep them warm for 24 h, and finally heat them to 600°C at a rate of 15°C / h and keep them warm for 16 h to obtain the above-mentioned slide rail prefabricated parts.

[0077] The adjustment in Example 22 was as follows:

[0078] Add 5.5% of water by weight of the total raw material components to the raw materials, mix them, vibrate and mold them after stirring, cure them for 20 h under the conditions of a temperature of 50°C and a relative humidity of 80%, heat them to 110°C at a rate of 20°C / h and keep them warm for 48 h after demolding, then heat them to 350°C at a rate of 30°C / h, keep them warm for 48 h, and finally heat them to 600°C at a rate of 20°C / h and keep them warm for 32 h to obtain the above-mentioned slide rail prefabricated parts.

[0079] The adjustment in Example 23 was as follows:

[0080] Add 5.0% of water by weight of the total raw material components to the above raw materials, mix them, vibrate and mold them after stirring, cure them for 25 h under the conditions of a temperature of 40°C and a relative humidity of 90%, heat them to 350°C at a rate of 15°C / h after demolding, keep them warm for 72 h, and finally heat them to 600°C at a rate of 18°C / h and keep them warm for 24 h to obtain the above-mentioned slide rail prefabricated parts. Comparative Examples Comparative Example 1

[0081] In this comparative example, on the basis of the method of Example 1, the particle size distribution of the mullite particles was adjusted. Specifically, mullite particles with a particle size of 3 - 5 mm were used. Comparative Example 2

[0082] On the basis of the method of Example 1, the particle size distribution of mullite particles was adjusted in this comparative example. Specifically, mullite particles with two particle sizes of 5-8 mm and 1-3 mm were used, and the weight ratio of 5-8 mm to 1-3 mm was 1:1. Comparative Example 3

[0083] On the basis of the method of Example 1, all alumina powder was replaced with alumina hollow spheres in this comparative example. Comparative Example 4

[0084] On the basis of the method of Example 1, the trehalose composite α-alumina powder was replaced with α-alumina powder in this comparative example. Comparative Example 5

[0085] On the basis of the method of Example 1, the trehalose composite α-alumina powder was replaced with a mixed alumina powder simply mixed with the same amount of trehalose and α-alumina powder in this comparative example.

[0086] Comparative Examples 6-11

[0087] On the basis of the method of Example 1, the structure of alumina powder was adjusted in Comparative Examples 6-11.

[0088] Among them, all the alumina powder in Comparative Example 6 was calcined alumina powder, all the alumina powder in Comparative Example 7 was activated alumina powder, all the alumina powder in Comparative Example 8 was trehalose composite α-alumina powder (Composite Alumina Powder 1), and the weight ratios of the three particle sizes d 50 of 4-6 µm, 1-2 µm, and 8-10 µm in the alumina powder in the above Comparative Examples 6-8 were all 4:6:90.

[0089] In addition, the alumina powder in Comparative Example 9 was composed of calcined alumina powder with a particle size d 50 of 4-6 µm, calcined alumina powder with a particle size d 50 of 1-2 µm, and trehalose composite α-alumina powder (Composite Alumina Powder 1) with a particle size d 50 of 8-10 µm, mixed in a weight ratio of 4:6:90; the alumina powder in Comparative Example 10 was composed of activated alumina powder with a particle size d 50 of 4-6 µm, activated alumina powder with a particle size d 50 of 1-2 µm, and trehalose composite α-alumina powder (Composite Alumina Powder 1) with a particle size d 50 of 8-10 µm, mixed in a weight ratio of 4:6:90; the alumina powder in Comparative Example 11 was composed of calcined alumina powder, activated alumina powder, and trehalose composite α-alumina powder (Composite Alumina Powder 1) mixed in a weight ratio of 4:6:90, and the particle size d 50 of all three kinds of alumina powder was 4-6 µm.

[0090] Performance detection test

[0091] The slide rail prefabricated parts prepared in the above Examples 1-23 and Comparative Examples 1-11 were subjected to high-temperature strength, corrosion resistance, and thermal shock resistance tests. The specific test results are shown in Table 2 below.

[0092] 1. High-temperature strength test

[0093] Referring to ASTM C133-24, the specific test conditions were as follows: The slide rail prefabricated parts were made into specimens with dimensions of Φ50×50 mm, kept at 1400 °C for 2 h, and after cooling to room temperature, the compressive strength (CCS) and modulus of rupture (MOR) were tested according to the standard procedure, with the unit of MPa.

[0094] 2. Corrosion resistance test

[0095] The specific test conditions were as follows: The slide rail prefabricated parts were made into specimens of 25 mm×25 mm×125 mm and immersed in an 80 °C, 20% H2SO4 solution for 168 hours, and the high-temperature mass loss rate was calculated (Δm≤1.5% was considered qualified), with the unit of %.

[0096] 3. Thermal shock resistance test

[0097] Referring to GB / T 30873-2014, the slide rail prefabricated parts were made into specimens with dimensions of 25 mm×25 mm×150 mm, and the surface needed to be polished to Ra≤1.6 μm. The temperature was raised to 1400 °C at a rate of 15 °C / min, kept at this temperature for 30 min, and then the specimens were quickly transferred to deionized water at room temperature (25±5 °C) and completely immersed for 3 min. After taking them out, they were dried in an oven at 110 °C for 1 hour and naturally cooled to room temperature. The above "heating - immersion - drying" process was repeated 5 times, and the modulus of rupture (MOR) after 5 cycles was tested, and the thermal shock strength retention rate (compared with the initial strength) was calculated, with the unit of %.

[0098] Table 2 Test results of Examples 1-23 and Comparative Examples 1-11

[0099] CCS (MPa) MOR (MPa) High temperature mass loss rate (%) Thermal shock strength retention rate (%) Example 1 155 28 0.6 93.8 Example 2 127 20 0.9 87.7 Example 3 136 24 0.8 90.5 Example 4 140 25 0.7 91.0 Example 5 132 22 0.8 89.3 Example 6 131 22 0.8 90.2 Example 7 142 26 0.9 89.5 Example 8 147 27 0.7 91.6 Example 9 149 27 0.7 90.8 Example 10 144 26 0.7 89.7 Example 11 131 22 0.8 88.5 Example 12 153 27 0.6 93.1 Example 13 152 27 0.6 92.9 Example 14 145 24 0.7 90.6 Example 15 130 20 0.9 87.6 Example 16 149 26 0.9 91.7 Example 17 142 23 0.7 90.3 Example 18 134 21 0.6 89.9 Example 19 146 24 1.0 91.0 Example 20 141 23 0.7 90.2 Example 21 150 27 0.6 92.2 Example 22 151 27 0.6 92.4 Example 23 127 19 1.0 86.3 Comparative Example 1 91 10 1.8 73.2 Comparative Example 2 100 12 1.7 76.6 Comparative Example 3 83 8 2.1 70.2 Comparative Example 4 101 12 1.7 76.4 Comparative Example 5 108 15 1.5 77.5 Comparative Example 6 107 14 1.6 77.0 Comparative Example 7 94 10 2.4 70.6 Comparative Example 8 113 16 1.3 80.1 Comparative Example 9 110 15 1.9 79.3 Comparative Example 10 102 12 1.7 76.5 Comparative Example 11 117 17 1.8 78.9

[0100] Combined with Table 2, by comparing the test results of Examples 1-23 and Comparative Examples 1-11, it can be obtained that the present invention uses mullite, alumina powder, and alumina hollow spheres in four particle size ranges to synergistically reduce the risk of thermal stress cracking. Then, calcium aluminate cement and silica fume react at high temperature to form a continuous ceramic network. The obtained slide rail preform has strong compressive strength (CCS) and flexural strength (MOR), a low high-temperature mass loss rate, and a high thermal shock strength retention rate. Therefore, it has excellent high-temperature strength, corrosion resistance, and thermal shock resistance, and can significantly improve the service life of the slide rail. In addition, compared with the method of not adding trehalose (Comparative Example 4), adding trehalose alone (Comparative Example 5), and using single or two kinds of alumina powder (Comparative Examples 6-11), the present invention needs to use alumina powder composed of calcined alumina powder with a particle size d 50 of 4-6 µm, activated alumina powder with a particle size d 50 of 1-2 µm, and trehalose composite α-alumina powder with a particle size d 50 of 8-10 µm to effectively exert the performance of each component. The obtained slide rail preform has excellent high-temperature strength and thermal shock resistance.

[0101] By comparing the inspection results of Examples 1-5, it can be obtained that in the present invention, as the amount of mullite increases, CCS and MOR show a trend of first increasing and then decreasing, the high-temperature mass loss rate continuously decreases, the thermal shock strength retention rate first increases and then stabilizes. The addition of alumina hollow spheres will slightly weaken the high-temperature mass loss rate and improve the thermal shock resistance to a certain extent. Combining with the component adjustment of alumina powder, calcium aluminate cement, silica fume, and water reducer, the corresponding CCS, MOR, high-temperature mass loss rate, and thermal shock strength retention rate will all change accordingly. Generally speaking, the scheme of 64-80% mullite is further preferably selected, and Examples 1, 3, and 4 all have excellent effects.

[0102] By comparing the test results of Example 1 and Examples 6-8, it can be obtained that the particle size distribution of mullite in the present invention will also affect the performance of the slide rail preform to a certain extent. Among them, mullite particles preferably composed of four particle size distributions of 5-8 mm 10~30%, 3-5 mm 10~40%, 1-3 mm 10~30%, and 0-1 mm 0~70% are further preferably composed of 5-8 mm 20%, 3-5 mm 35%, 1-3 mm 25%, and 0-1 mm 20%.

[0103] By comparing the test results of Example 1 and Examples 9-17, it can be obtained that different configurations of alumina powder in the present invention have a greater impact on the high-temperature strength and thermal shock resistance of the slide rail preform. The present invention preferably uses calcined alumina powder with a particle size d 50 of 4-6 µm, and the particle size d 50Activated alumina powder with a particle size of 1 - 2 µm and trehalose composite α-alumina powder with a particle size d 50 50 is alumina powder composed of trehalose composite α-alumina powder with a particle size of 8 - 10 µm and activated alumina powder with a particle size of 1 - 2 µm, mixed in a weight ratio of 1 - 6:3 - 9:85 - 96. Among them, the trehalose composite α-alumina is preferably obtained by the preparation method of "mixing α-alumina powder with a trehalose solution to form a slurry, injecting the slurry into a mold for vibration and exhaust, curing in an environment with a humidity of 80 - 100% and a temperature of 30 - 40 °C for 24 - 48 h, demolding and then subjecting to low-temperature pre-sintering at 100 - 150 °C, and grinding after removing moisture", and the corresponding weight ratio of α-alumina powder to trehalose is 3:1.

[0104] Comparing the test results of Example 1 with those of Examples 18 - 20, it can be obtained that different parameters of the aluminate cement and alumina hollow spheres in the present invention will also affect the overall performance of the slide rail prefabricated part to a certain extent. Therefore, the present invention further defines that the alumina content in the aluminate cement is 65 - 70%, and the calcium oxide content is 29 - 33%; the alumina hollow spheres preferably have a purity of ≥99%, a particle size of 0.2 - 0.5 mm, and a bulk density of 0.8 - 0.9 g / cm 3 .

[0105] Comparing the test results of Example 1 with those of Examples 21 - 23, it can be obtained that when preparing the slide rail prefabricated part in the present invention, high-humidity curing and temperature-humidity co-control (20 - 50 °C, 80 - 100% RH) are used to optimize the hydration structure of the material, and then stepped heating and segmented rate control (initial heat preservation at 110 - 115 °C (24 - 48 h) to remove free water and residual stress first, medium-temperature heat preservation at 350 °C (24 - 48 h) can promote the transformation of mineral phases, and high-temperature heat preservation at 600 °C (16 - 32 h) can strengthen grain boundary bonding) are used to reduce internal defects, thereby avoiding microstructural phase change stress caused by temperature mutation, and thus ensuring excellent high-temperature strength, corrosion resistance and thermal shock resistance of the slide rail prefabricated part.

[0106] In summary, the high-strength and wear-resistant slide rail prefabricated part prepared in this application has excellent high-temperature strength, corrosion resistance and thermal shock resistance, and can be well applied to the slide rails of forging heating furnaces.

[0107] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A high-strength wear-resistant slide rail prefabricated component, characterized in that: The invention comprises the following raw material components by weight percentage: 39.5-90% of mullite particles, 3.3-10% of alumina powder, 2.4-10% of calcium aluminate cement, 2.4-10% of silica powder, 0-30% of alumina hollow spheres, and 0.1-0.5% of water reducing agent; The mullite is composed of the following particle gradations, and the particle size of each particle grade and the weight percentage of the mullite are: 5-8mm 10~30%; 3-5mm 10~40%; 1-3mm 10~30%; 0-1mm 0~70%; The alumina powder has a particle size of d 50 Calcined alumina powder with a particle size of 4-6µm 50 Activated alumina powder with a particle size of 1-2µm 50 It is a mixture of 8-10µm trehalose composite α-alumina powder.

2. The high-strength wear-resistant slide rail prefabricated component according to claim 1 is characterized in that: The weight ratio of the calcined alumina powder, the activated alumina powder and the trehalose composite alpha-alumina powder is 1-6:3-9:85-96.

3. The high-strength wear-resistant slide rail prefabricated component according to claim 1 is characterized in that: The preparation method of the trehalose composite α-alumina powder comprises the following steps: Mix α-alumina powder and trehalose solution to make slurry, inject the slurry into a mold, vibrate and exhaust, place it in an environment with a humidity of 80-100% and a temperature of 30-40°C for curing for 24-48 hours, and place it at 100-150°C for low-temperature pre-sintering after demoulding, remove moisture and then grind it.

4. The high-strength wear-resistant slide rail prefabricated component according to claim 3 is characterized in that: The weight ratio of the α-alumina powder to the trehalose is 3:

1.

5. The high-strength wear-resistant slide rail prefabricated component according to claim 1 is characterized in that: The calcium aluminate cement contains 65-70% aluminum oxide and 29-33% calcium oxide.

6. The high-strength wear-resistant slide rail prefabricated component according to claim 1, characterized in that: The purity of the hollow alumina spheres is ≥99%, the particle size is 0.2-0.5 mm, and the bulk density is 0.8-0.9 g / cm 3 .

7. The high-strength wear-resistant slide rail prefabricated component according to claim 1 is characterized in that: The water reducing agent is at least one of sodium tripolyphosphate, sodium hexametaphosphate and boric acid.

8. A method for preparing a high-strength wear-resistant slide rail prefabricated component, characterized in that: The method for preparing the high-strength wear-resistant slide rail prefabricated component according to any one of claims 1 to 7 comprises the following steps: Take a set amount of raw material components, add 4.5-5.5% of water accounting for the total weight of the raw material components to mix, stir and vibrate to form, cure for 20-30 hours at a temperature of 20-50°C and a relative humidity of 80-100%, heat to 110-115°C at 10-20°C / h after demolding, keep warm for 24-48 hours, then heat to 350°C at 15-30°C / h, keep warm for 24-48 hours, finally heat to 600°C at 15-20°C / h, keep warm for 16-32 hours, and obtain the high-strength wear-resistant slide rail prefabricated component.

9. Use of the high-strength wear-resistant slide rail preform according to any one of claims 1 to 7 in forging heating furnace slide rails.